According to 3GPP TS23.682 specification, the delivery report in the existing T4 Trigger Delivery Flow can only confirm if the trigger data is received or not, i.e., the delivery report is only a confirmation on transport level because of the limitation of SMS (Short Messaging Service). The delivery report cannot transfer the information on the MTC (Machine Type Communication) application level, such as whether the MTC application accepts the trigger payload, not to mention delivering a corresponding trigger result from UE (User Equipment) to related target device. Here, the target device may be a network element (NE) or a UE, for example, MTC-IWF (MTC Interworking Function), SCS (Service Capability Server), AS (Application Server) or an origination UE for sending the trigger data.
However, it is basic requirement for MTC to deliver a trigger response to the originator, e.g., MTC-IWF, SCS, AS or origination UE for sending the trigger data. For example, in a scenario of sensor query, an effective way is necessarily sending back the query result to a trigger originator right away. According to the existing TS23.682 specification, the MTC devices have to send a separated report message back to the MTC application of the originator, which results in a plurality of extra message flows.
Therefore, in the prior art, for MTC scene, the receiver for the trigger message has to send back messages twice to the originator, i.e., the delivery report message only including confirmation of receipt of the trigger message, and the report message for the trigger result. It would undoubtedly bring more signaling overheads, thereby occupying too many channel resources.